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/*
* (C) 2008 by Pablo Neira Ayuso <pablo@netfilter.org>
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "internal/stack.h"
struct stack {
int num_elems;
int max_elems;
size_t elem_size;
char *data;
};
struct stack *stack_create(size_t elem_size, int max_elems)
{
struct stack *s;
s = calloc(sizeof(struct stack), 1);
if (s == NULL)
return NULL;
s->data = calloc(elem_size * max_elems, 1);
if (s->data == NULL) {
free(s);
return NULL;
}
s->elem_size = elem_size;
s->max_elems = max_elems;
return s;
}
void stack_destroy(struct stack *s)
{
free(s->data);
free(s);
}
int stack_push(struct stack *s, void *data)
{
if (s->num_elems >= s->max_elems) {
errno = ENOSPC;
return -1;
}
memcpy(s->data + (s->elem_size * s->num_elems), data, s->elem_size);
s->num_elems++;
return 0;
}
int stack_pop(struct stack *s, void *data)
{
if (s->num_elems <= 0) {
errno = EINVAL;
return -1;
}
s->num_elems--;
memcpy(data, s->data + (s->elem_size * s->num_elems), s->elem_size);
return 0;
}
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